Video-signal recording and playback apparatus, video-signal recording and playback method, and recording medium

ABSTRACT

Disclosed is a video-signal recording and playback apparatus for recording or playing back a video signal, the video-signal recording and playback apparatus comprising: extracting means for extracting a static picture from a sequence of video signals with a predetermined timing; judgment means for forming a judgment as to whether or not a static picture extracted by the extracting means can be used as a representative picture; and setting means for setting the static picture as a representative picture in accordance with an outcome of a judgment formed by the judgment means.

BACKGROUND OF THE INVENTION

[0001] In general, the present invention relates to a video-signalrecording and playback apparatus, a video-signal recording and playbackmethod and a recording medium. More particularly, the present inventionrelates to a video-signal recording and playback apparatus, avideo-signal recording and playback method and a recording mediumsuitable for a case in which a recommended position to start anoperation to playback a video signal from a recording medium isprovided.

[0002] In order to allow the user to grasp the contents of a programrecorded on a recording medium or the contents of a group of suchprograms, or in order to search such a recording medium for a program,there is provided a method whereby a plurality of shrunk static picturesor moving pictures each representing a program or a scene is displayedon a screen and the user is allowed to specify one of the displayedpictures in order to select a desired program or a desired scene of aprogram. A shrunk static picture is referred to as a thumb nail.

[0003] With the conventional method, a picture appearing right after thestart of a recording operation is captured or pictures are captured atfixed intervals to be used as a representative picture of a program or ascene.

[0004] By the way, there are raised problems described below in themethod cited above whereby, in the conventional signal recording andplayback apparatus, pictures are browsed at fixed intervals to be usedas representatives of programs or scenes.

[0005] For example, a picture taken as a representative picture of aprogram is not a scene of a program. Instead, a picture taken as arepresentative picture of a program is a picture in a CM (commercial) ora picture of a blue sky. Such a representative picture of a programcannot be used to infer the contents of the program at all. In such acase, it is generally difficult for the user to select a desired programor a desired scene in a program.

SUMMARY OF THE INVENTION

[0006] It is thus an object of the present invention addressing theproblems described above to provide a capability of extracting aprogram's representative picture allowing the user to select a desiredone among programs or a desired one among a program's scenes.

[0007] In carrying out the invention and according to one aspectthereof, there is provided a video-signal recording and playbackapparatus for recording or playing back a video signal, the video-signalrecording and playback apparatus comprising: extracting means forextracting a static picture from a sequence of video signals with apredetermined timing; judgment means for forming a judgment as towhether or not a static picture extracted by the extracting means can beused as a representative picture; and setting means for setting thestatic picture as a representative picture in accordance with an outcomeof a judgment formed by the judgment means.

[0008] According to a second aspect of the invention, there is provideda video-signal recording and playback method adopted in a video-signalrecording and playback apparatus for recording or playing back a videosignal, the video-signal recording and playback method comprising: anextracting step of extracting a static picture from a sequence of videosignals with a predetermined timing; a judgment step of forming ajudgment as to whether or not the static picture extracted at theextracting step can be used as a representative picture; and a settingstep of setting the static picture as a representative picture inaccordance with an outcome of a judgment formed at the judgment step.

[0009] According to a third aspect of the invention, there is provided arecording medium for recording a program for controlling a video-signalrecording and playback apparatus for recording or playing back a videosignal, wherein the program is a computer readable program, the programcomprising: an extracting step of extracting a static picture from asequence of video signals with a predetermined timing; a judgment stepof forming a judgment as to whether or not the static picture extractedat the extracting step can be used as a representative picture; and asetting step of setting the static picture as a representative picturein accordance with an outcome of a judgment formed at the judgment step.

[0010] With this configuration, in accordance with the presentinvention's video-signal recording and playback apparatus andvideo-signal recording and playback method and a program recorded in therecording medium provided by the present invention, a static picture isextracted from a sequence of video signals with a predetermined timing;a judgment as to whether or not a static picture extracted at theextracting step can be used as a representative picture is formed; andthe static picture is set on a representative picture in accordance withan outcome of the judgment. As a result, it is possible to extract aprogram's representative picture allowing a desired program or a desiredscene to be selected.

[0011] The above and other objects, features and advantages of thepresent invention will become apparent from the following descriptionand the appended claims, taken in conjunction with the accompanyingdrawings in which like parts or elements denoted by like referencesymbols.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a block diagram showing a typical configuration of ahard-disc recorder implemented by an embodiment of the presentinvention;

[0013]FIGS. 2A and 2B are diagrams showing dimensions of the screen of apicture subjected to a judgment as to whether or not the picture is ameaningless picture.

[0014]FIGS. 3A and 3B are explanatory diagrams showing a method ofdetecting a meaningless picture by using a histogram;

[0015]FIGS. 4A and 4B are explanatory diagrams showing a method ofdetecting a meaningless picture by using a histogram;

[0016]FIGS. 5A and 5B are explanatory diagrams showing a method ofdetecting a meaningless picture by using a histogram;

[0017]FIG. 6 is an explanatory diagram showing a method of detecting ameaningless picture by using edges of the picture;

[0018]FIG. 7 is a diagram showing a typical GUI (Graphical UserInterface) display of a set of title screens; and

[0019]FIG. 8 is a diagram showing a typical GUI display of a set ofsearched scenes pertaining to a selected program.

PREFERRED EMBODIMENT OF THE INVENTION

[0020] A hard-disc recorder implemented by a preferred embodiment of thepresent invention is explained by referring to diagrams as follows.

[0021]FIG. 1 is a block diagram showing a typical configuration of ahard-disc recorder. An antenna 1 receives a television broadcast andsupplies a signal of the broadcast to a tuner 2. In accordance with acommand issued by a system controller 31, the tuner 2 extracts a signalof a program of a predetermined channel from the television broadcast'ssignal received from the antenna 1. The extracted signal is supplied toan input switch 5.

[0022] An external apparatus not shown in the figure supplies an S videosignal to a terminal a of a switch 9 by way of an external video inputterminal 3-1. An S video signal is separated signals comprising a Ysignal (luminance signal) and a C signal (chrominance signal). Anexternal apparatus not shown in the figure supplies a composite videosignal to the input switch 5 by way of an external video input terminal3-2. An external apparatus not shown in the figure supplies an audiosignal to the input switch 5 by way of an external video input terminal4.

[0023] In accordance with a command issued by the system controller 31,the input switch 5 selects a desired signal from the video signal andthe audio signal, which are supplied thereto. If the selected signal isthe composite video signal, the input switch 5 supplies the selectedcomposite video signal to a YC circuit 8. If the selected signal is theaudio signal, on the other hand, the input switch 5 supplies theselected audio signal to an A/D (Analog to Digital) converter 6.

[0024] The A/D converter 6 converts an audio signal received from theinput switch 5 into digital data by A/D conversion and supplies thedigital data to an MPEG (Moving Picture Experts Group) audio encoder 7.The A/D converter 6 also supplies the digital audio data obtained as aresult of the A/D conversion to a terminal b of the input switch 25. Inaccordance with a command issued by the system controller 31, the MPEGaudio encoder 7 carries out a compression process adopting an MPEGtechnique on the digital audio data received from the A/D converter 6 togenerate an audio ES (elementary stream). The MPEG audio encoder 7supplies the audio ES to a multiplexer/demultiplexer 14.

[0025] In accordance with a command issued by the system controller 31,a YC separation circuit 8 separates a composite video signal receivedfrom the input switch 5 into a luminance signal (or a Y signal) and achrominance signal (or a C signal). The YC separation circuit 8 suppliesthe Y signal and the C signal to an NTSC (National Television SystemCommittee) decoder 10 by way of a terminal b of the switch 9. Inaccordance with a command issued by the system controller 31, the switch9 changes its contact to a terminal a to forward an S signal receivedfrom an external apparatus to the NTSC decoder 10. Also in accordancewith a command issued by the system controller 31, the switch 9 changesits contact to a terminal b to forward Y and C signals received from theYC separation circuit 8 to the NTSC decoder 10.

[0026] In accordance with a command issued by the system controller 31,the NTSC decoder 10 carries out processes such as A/D conversion andchroma encode processing on a video signal received from the switch 9 toconvert the video signal into a digital component video signal referredto hereafter as picture data. The NTSC decoder 10 supplies the picturedata to a video-signal preprocessing circuit 12. The NTSC decoder 10also generates a clock signal based on a horizontal synchronizationsignal of a received video signal. In addition, the NTSC decoder 10supplies a field-identifying signal, a vertical synchronization signaland the horizontal synchronization signal obtained as a result ofsynchronous separation to a synchronization-signal control circuit 11.

[0027] In accordance with a command issued by the system controller 31,the synchronization-signal control circuit 11 generates clock andsynchronization signals with the field-identifying signal, the verticalsynchronization signal and the horizontal synchronization from the NTSCdecoder 10 used as a reference. The synchronization-signal controlcircuit 11 supplies the generated clock and synchronization signals to avariety of components.

[0028] In accordance with a command issued by the system controller 31,the video-signal preprocessing circuit 12 carries out video signalprocessing such as pre-filtering on picture data received from the NTSCdecoder 10 to generate a representative picture. The video-signalpreprocessing circuit 12 supplies the representative picture to an MPEGvideo encoder 13 and a video-signal post-processing circuit 20. Inaccordance with a command issued by the system controller 31, the MPEGvideo encoder 13 carries out an encoding process such as DCT (DiscreteCosine Transform) processing on picture data received from thevideo-signal preprocessing circuit 12 to generate an elementary streamof the picture. The MPEG video encoder 13 supplies the elementary streamto the multiplexer/demultiplexer 14.

[0029] In accordance with a command issued by the system controller 31,in a recording operation, the multiplexer/demultiplexer 14 multiplexesan elementary stream of a picture and an audio elementary stream, whichhas completed compression adopting the MPEG technique, as well as avariety of control signals to generate typically an MPEG TS (transportstream). The video-signal preprocessing circuit 12 supplies the MPEG TSto a buffer controller 17. In a playback operation, on the other hand,the multiplexer/demultiplexer 14 demultiplexes an MPEG TS received fromthe buffer controller 17 to extract a PES (Packetized Elementary Stream)from the MPEG TS. The multiplexer/demultiplexer 14 supplies theextracted PES to an MPEG AV decoder 19.

[0030] In accordance with a command issued by the system controller 31,the buffer controller 17 executes control to intermittently supply thetransport stream received continuously from themultiplexer/demultiplexer 14 to an HDD (Hard-Disc Drive) 18. While theHDD 18 is carrying out a seek operation, for example, a transport streamcannot be written into a hard disc of the HDD 18. In this case, thetransport stream is stored temporarily in a buffer. As the seekoperation is completed, allowing a transport stream to be written intothe hard disc, the stream is read out from the buffer and stored intothe hard disc at a rate higher than a rate of inputting data to thebuffer. In this way, a transport stream received continuously from themultiplexer/demultiplexer 14 can be all written into the hard disc ofthe HDD 18.

[0031] The buffer controller 17 also executes control to store signalreceived from the HDD 18 intermittently into a buffer so that the storedsignal can be supplied to the multiplexer/demultiplexer 14 as acontinuous transport stream.

[0032] In accordance with a command issued by the system controller 31,the HDD 18 stores a transport stream received from the buffer controller17 intermittently into the hard disc at a predetermined address. The HDD18 also seeks a predetermined address, reads out a transport stream fromthe address and supplies the stream to the buffer controller 17.

[0033] The buffer controller 17 and the HDD 18 adopt an IDE (IntegratedDrive Electronics) protocol. It should be noted, however, that anyprotocol can be adopted in the present invention as long as the protocolis used for recording a transport stream.

[0034] In accordance with a command issued by the system controller 31,the MPEG AV decoder 19 separates a PES received from themultiplexer/demultiplexer 14 into a video elementary stream and an audioelementary stream. The MPEG AV decoder 19 then carries out apredetermined decoding process on the elementary streams, supplyingvideo data of a base band to the video-signal post-processing circuit 20and audio data of the base band to an audio-signal post-processingcircuit 24.

[0035] In accordance with a command issued by the system controller 31,the video-signal post-processing circuit 20 switches the input from avideo signal supplied by the video-signal preprocessing circuit 12 tovideo data of the base band supplied by the MPEG AV decoder 19 or viceversa, and synthesizes the video signal and the video data. Thevideo-signal post-processing circuit 20 also carries out filtering onthe input data and supplies the filtered data to an on-screen displaycircuit 21. In addition, the video-signal post-processing circuit 20also provides a GUI (Graphic User Interface) for displaying pictures andgenerates a representative picture of a program represented by picturedata. The video-signal post-processing circuit 20 then pastes therepresentative picture of a program on a window and supplies the windowto the on-screen display circuit 21.

[0036] In accordance with a command issued by the system controller 31,the on-screen display circuit 21 converts text information intocorresponding picture data and superposes the picture data obtained as aresult of the conversion on picture data received from the video-signalpost-processing circuit 20. The on-screen display circuit 21 thensupplies the superposed picture data to an NTSC encoder 22.

[0037] In accordance with a command issued by the system controller 31,the NTSC encoder 22 converts picture data (or a component digitalsignal) received from the on-screen display circuit 21 into Y and Csignals. Then, the NTSC encoder 22 generates an S video signalcompleting a D/A conversion process and an analog composite videosignal. The NTSC encoder 22 supplies the S video signal completing a D/Aconversion process and the analog composite video signal to an externalapparatus through external video output terminals 23-1 and 23-2.

[0038] In accordance with a command issued by the system controller 31,the audio-signal post-processing circuit 24 carries out processes suchas filtering, fading and conversational-speed conversion on audio dataof the base band received from the MPEG AV decoder 19, supplying aresult of the processes to a terminal a of a switch 25.

[0039] In accordance with a command issued by the system controller 31,the switch 25 sets its contact at a terminal a to supply audio datareceived from the audio-signal post-processing circuit 24 to a D/Aconverter 26, or a terminal b to supply audio data received from the A/Dconverter 6 to the D/A converter 26. The D/A converter 26 converts audiodata received from the switch 25 into analog data in D/A conversion andsupplies the analog data to an external apparatus by way of an externalaudio output terminal 27.

[0040] The system controller 31 reads out a program from a ROM(Read-Only Memory) 33 through a host bus 32 and executes the program tocontrol other components. A RAM (Random-Access Memory) 34 is usedproperly for storing a program and data which are required forcontrolling the other components. The system controller 31, the ROM 33and the RAM 34 are connected to each other and to an input/outputinterface 35 by the host bus 32. The input/output interface 35 isconnected to a drive 36 for driving a magnetic disc 41, an optical disc42, a magneto-optical disc 43 or a semiconductor memory 44. Theinput/output interface 35 is also connected to an input unit 37including a keyboard, a mouse, buttons, switches and a remote commander.

[0041] The hard-disc recorder is capable of inputting and outputting notonly an analog signal, but also digital data. For example, an IRD(Integrated Receiver Decoder) not shown in the figure is allowed tosupply a transport stream to a digital interface 15 through an IEEE (theInstitute of Electrical and Electronic Engineers)-1394 serial busconnected to a digital input/output terminal 16. In accordance with acommand issued by the system controller 31, the digital interface 15carries out an interfacing process to supply the input transport streamto the multiplexer/demultiplexer 14. In accordance with a comm andissued by the system controller 31, the multiplexer/demultiplexer 14outputs the transport stream received from the digital interface 15 tothe buffer controller 17.

[0042] The multiplexer/demultiplexer 14 also outputs a transport streamreceived from the buffer controller 17 to the digital interface 15. Thedigital interface 15 supplies the transport stream received from themultiplexer/demultiplexer 14 to the external IRD through a digitalinput/output terminal 16 and the IEEE-1394 serial bus. The IRD outputsthe transport stream on a monitor connected thereto to be displayed onthe monitor.

[0043] In this embodiment, the hard-disc recorder is connected to theIRD as described above. It should be noted, however, that the scope ofthe present invention is not limited to this configuration. For example,the hard-disc recorder can also be connected to a personal computer oranother apparatus.

[0044] In addition, while a video signal is compressed by adoption ofthe MPEG technique, the scope of the present invention is not limited tothis technique. That is to say, other compression techniques can also beadopted.

[0045] Furthermore, in place of a hard disc of the HDD 18, it is alsopossible to use other recording media such as an optical disc, amagneto-optical disc and a solid-state memory.

[0046] Next, a method of determining a representative picture of aprogram is explained.

[0047] Normally, a picture appearing right after the start of arecording operation is used as a picture representing a program. As analternative, a picture appearing after a predetermined lapse of timesince the start of a recording operation can also be used as a screenrepresenting a program. The representative picture is referred tohereafter as a title screen.

[0048] As a program's representatives used for knowing the contents ofthe program, it is possible to use video signals taken at fixedintervals. The picture is referred to hereafter as a searched scene.

[0049] Since the system controller 31 recognizes the start of arecording operation and a predetermined lapse of time since the start ofa recording operation, pictures appearing at the start of a recordingoperation and after a predetermined lapse of time since the start of arecording operation can be cataloged with ease. The pictures arenormally supplied to the video-signal preprocessing circuit 12 whichdetects the pictures to form a judgment as to whether or not the pictureis suitable for use as a representative picture of a program.

[0050] First of all, in detection of a commercial, the video-signalpreprocessing circuit 12 detects a scene-change portion of a picture andsupplies a result of detection to the system controller 31.

[0051] The system controller 31 detects a commercial by using the resultof detection and audio information received from another system.

[0052] As a technique of detecting a commercial, it is possible to adoptan already proposed method such as a method disclosed in Japanese PatentLaid-open No. Hei 9-25494. Of course, another method can also be adoptedfor detecting a commercial.

[0053] In this way, the system controller 31 is capable of recognizingthat a picture to be cataloged as a representative picture of a programis a part of a commercial and, hence, making a decision not to catalogthe picture as a representative picture of a program.

[0054] If a title screen is a commercial, a screen appearing uponcompletion of the commercial is cataloged as a title screen. As analternative, a screen appearing after a predetermined lapse of timesince completion of the commercial is cataloged as a title screen.

[0055] If a searched scene is a commercial, a thinning process is simplyprocessed or a scene appearing upon completion of the commercial is usedas a searched scene and, after a predetermined lapse of time, processingis resumed.

[0056] The following description explains a method of detecting apicture having too a small amount of information to infer or grasp aprogram. An example of such information is a picture, most of whichshows a blue sky. Such a picture is referred to hereafter as ameaningless picture.

[0057] The following description explains one of methods of determiningthat a picture is a meaningless picture. The description begins with anexplanation of a procedure of determining that a picture is ameaningless picture by using a histogram of a color signal withreference to FIGS. 2A to 5B.

[0058] The video-signal preprocessing circuit 12 always acquires ahistogram of a video signal and supplies a result of acquisition to thesystem controller 31.

[0059] As shown in FIGS. 2A and 2B, the dimensions of a screen is awidth of x pixels and a height of y pixels. A histogram is spreadhorizontally into n grades each representing the color level of a pixel.In the case of a color signal, a Cr histogram and a Cb histogram areprovided independently.

[0060] In general, a picture with a small amount of information resultedin a histogram tending to be concentrated at particular grades. Byutilizing this phenomenon, a degree of histogram distribution exceedinga threshold value determined in advance is regarded to indicate that thepicture is a meaningless picture.

[0061] In the case of histogram 1 shown in FIGS. 3A and 3B, for example,the Cr and Cb histograms are each distributed over all grades,indicating that the picture is a meaningful picture.

[0062] In the case of histogram 2 shown in FIGS. 4A and 4B, on the otherhand, the Cr histogram is concentrated at low grades while the Cbhistogram is concentrated at high grades, indicating a picture like thatof a blue sky. In this case, the picture can be determined to be ameaningless picture not suitable for use as a representative picture ofa program.

[0063] Also in the case of histogram 3 shown in FIGS. 5A and 5B, the Crand Cb histograms are both concentrated at low grades, indicating thatthe picture is a meaningless picture as well.

[0064] To put it concretely, a threshold value represented by a dashedline is set for each of histograms 1 to 3 shown in FIGS. 3A to 5Brespectively. The total area of bar regions above the threshold value isevaluated to form a judgment as to whether or not a picture is ameaningless picture.

[0065] In the formation of such a judgment, it is possible to use avariety of quantity combinations such as the sum of total areas for boththe Cb and Cr diagrams, the individual total areas and a logical sum ofluminance results described earlier.

[0066] A characteristic of a meaningless picture is unclear pictureedges as observed in a blurring picture. Determination of a meaninglesspicture by detection of such a characteristic is explained by referringto FIG. 6.

[0067] In FIG. 6, notation Dij denotes a luminance level of a pixellocated at coordinates (i, j) on a field picture. By applying luminancelevel Dij to Eq. (1) given below, a horizontal-direction edge amount EHcan be computed. By the same token, by applying luminance level Dij toEq. (2) given below, a vertical-direction edge amount EV can becomputed. $\begin{matrix}{{EH} = {\sum\limits_{i = 0}^{n}{\sum\limits_{j = 0}^{m}{{abs}( {{Dij} - {Dij} + 1} )}}}} & (1) \\{{EV} = {\sum\limits_{i = 0}^{n}{\sum\limits_{j = 0}^{m}{{abs}( {{Dij} - {{Di}( {j + 1} )}} )}}}} & (2)\end{matrix}$

[0068] If the horizontal-direction edge amount EH and thevertical-direction edge amount EV are both smaller than a predeterminedthreshold value, the picture is determined to be a meaningless picture.

[0069] As such, a meaningless picture is determined by adopting thetechniques described above. It should be noted, however, that anothertechnique can also be adopted.

[0070] If a meaningless picture becomes a candidate for therepresentative picture of a program, the system controller 31 carriesout a thinning process as is the case with a commercial and a process touse a following picture as a representative picture of a program and notto use the meaningless picture as a representative picture of a program.

[0071] A program's representative picture detected as described above isrecorded. When a representative picture of a program is determined byusing a video signal, an audio signal and another signal, informationrepresented by the signals is recorded on a recording medium. A methodof recording such information is explained as follows.

[0072] Information on a representative picture of a program is recordedin the form of time codes or as the picture itself or as a shrunkpicture in a recording medium separately from a video signal. In thiscase, the representative picture of a program can be recorded in arecording medium different from a recording medium for recording thevideo signal. As an alternative, the representative picture of a programand the video signal can also be recorded in different areas of the samerecording medium.

[0073] A typical method for playing back a representative picture of aprogram recorded as described above is explained as follows.

[0074] The explanation begins with a description of a method fordisplaying a representative picture of a program for each programpertaining to a group of programs recorded on a recording medium. Atitle screen, which is detected as a representative picture of a programand shows as many titles as programs, is displayed as shown in FIG. 7.By looking at this screen, the user is capable of grasping what programsare recorded.

[0075] In addition, by displaying a plurality of searched scenespertaining to a selected program as shown in FIG. 8, the user is allowedto look at the scenes and grasp the contents of the program in a shortperiod of time.

[0076] As described above, in accordance with the present invention, ameaningless picture is detected and not used as a representative pictureof a program to give the following effects.

[0077] In accordance with an embodiment of the present invention, thelocation of a representative picture of a program to be recorded in arecording operation and/or the representative picture of a programitself are stored in the recording operation. In this way, the user iscapable of looking at a table of representative pictures of a programpertaining to a group of recorded programs in a playback operation. Suchrepresentative pictures of a program are useful to the user in graspingthe group of programs recorded in a recording medium instantly.

[0078] In addition, the user is also capable of looking at a set ofrepresentative scenes pertaining to a specific program. Such a set ofrepresentative scenes is convenient, making it easy to search thespecific program for a scene of interest.

[0079] The larger the recording capacity of a recording medium, the morethe programs that can be recorded on the recording medium. With a largenumber of programs recorded in the recording medium, it is generallyconsidered to be difficult to select a desired specific program. Thepresent invention is specially effective for such a case.

[0080] By the way, the series of pieces of processing described abovecan be carried out by hardware or through execution of software. Whenexecution of software is selected for carrying out the series of piecesof processing, a variety of programs composing the software are executedby a computer incorporated in special hardware. As an alternative, theprograms are installed in a recording memory employed in typically ageneral-purpose personal computer capable of executing the programs tocarry out the pieces of processing.

[0081] As shown in FIG. 1, recording media for presenting a program tothe user is distributed separately from the computer. In order topresent a program to the user, however, the use of package media is notmandatory. Examples of the recording media are the magnetic disc 41including a floppy disc, the optical disc 42 including a CD-ROM(Compact-Disc Read-Only Memory) and a DVD (Digital Versatile Disc), themagneto-optical disc 43 including an MD (Mini Disc) and thesemiconductor memory 44. As an alternative, a program can also bepresented to the user by incorporating the program in the computer inadvance. That is to say, the program is stored in a ROM or a hard discincluded in the HDD.

[0082] It should be noted that, in this specification, while stepsprescribed in a program recorded in a recording medium can of course beexecuted sequentially along the time axis in an order the steps areprescribed in the program, the steps are not always executedsequentially along the time axis. That is to say, a program may includesteps that are executed concurrently or independently.

[0083] In addition, the technical term ‘system’ used in thisspecification means the whole equipment comprising a plurality ofapparatuses.

[0084] While a preferred embodiment of the present invention has beendescribed using specific terms, such description is for illustrativepurposes only, and it is to be understood that changes and variationsmay be made without departing from the spirit or scope of the followingclaims.

What is claimed is:
 1. A video-signal recording and playback apparatusfor recording or playing back a video signal, said video-signalrecording and playback apparatus comprising: extracting means forextracting a static picture from a sequence of video signals with apredetermined timing; judgment means for forming a judgment as towhether or not a static picture extracted by said extracting means canbe used as a representative picture; and setting means for setting saidstatic picture as a representative picture in accordance with an outcomeof a judgment formed by said judgment means.
 2. A video-signal recordingand playback apparatus according to claim 1, wherein said judgment meansis capable of forming a judgment as to whether or not a static pictureextracted by said extracting means can be used as a representativepicture on the basis of whether or not said static picture is a part ofa commercial.
 3. A video-signal recording and playback apparatusaccording to claim 1, wherein said judgment means is capable of forminga judgment as to whether or not a static picture extracted by saidextracting means can be used as a representative picture on the basis ofa histogram of said static picture.
 4. A video-signal recording andplayback apparatus according to claim 1, wherein said judgment means iscapable of forming a judgment as to whether or not a static pictureextracted by said extracting means can be used as a representativepicture on the basis of an edge of said static picture.
 5. Avideo-signal recording and playback method adopted in a video-signalrecording and playback apparatus for recording or playing back a videosignal, said video-signal recording and playback method comprising: anextracting step of extracting a static picture from a sequence of videosignals with a predetermined timing; a judgment step of forming ajudgment as to whether or not said static picture extracted at saidextracting step can be used as a representative picture; and a settingstep of setting said static picture as a representative picture inaccordance with an outcome of a judgment formed at said judgment step.6. A recording medium for recording a program for controlling avideo-signal recording and playback apparatus for recording or playingback a video signal, wherein said program is a computer readableprogram, said program comprising: an extracting step of extracting astatic picture from a sequence of video signals with a predeterminedtiming; a judgment step of forming a judgment as to whether or not saidstatic picture extracted at said extracting step can be used as arepresentative picture; and a setting step of setting said staticpicture as a representative picture in accordance with an outcome of ajudgment formed at said judgment step.